Explorations in server-side rendering web components.
When ssr.js is injected in a page built with shadow-dom, it clones that live document, replaces all
shadowRoots with <shadow-root>, replaces styles in shadowRoots with placeholder <shadow-style> elements keyed to
a master deduped shadow-styles list that's put in a template in head, and injects the <shadow-root> element definition.
For now it also removes all imports/scripts so it's just a static page (this exploration does not cover re-inflating/mounting the custom elements, only static rendering for first paint). The script will open a new tab with the source of the
cloned ssr-ified document.
e.g. open http://polymerlabs.github.io/app-layout/templates/pesto/?dom=shadow, then paste this in the console:
var s = document.createElement('script');
s.src = 'https://polygit2.appspot.com/wc-ssr+kevinpschaaf+:master/components/wc-ssr/ssr.js';
s.onload = function() { window.ssrify(true); };
document.head.appendChild(s);Then check out view-source of the newly opened tab (look for blocked popup) to see the declarative <shadow-roots> in the source, and in the elements panel you should see real #shadow-roots.